CGAN-EB: A Non-parametric Empirical Bayes Method for Crash Hotspot Identification Using Conditional Generative Adversarial Networks: A Simulated Crash Data Study

TL;DR

This paper introduces CGAN-EB, a novel non-parametric empirical Bayes method using conditional generative adversarial networks to identify crash hotspots, outperforming traditional models in realistic traffic data scenarios.

Contribution

The paper proposes CGAN-EB, a deep neural network-based empirical Bayes approach that models crash data without parametric assumptions, improving hotspot detection in practical conditions.

Findings

CGAN-EB matches NB-EB when data fit negative binomial assumptions.

CGAN-EB outperforms NB-EB with low crash counts and non-log-linear relationships.

Simulation results demonstrate CGAN-EB's robustness in real-world scenarios.

Abstract

In this paper, a new non-parametric empirical Bayes approach called CGAN-EB is proposed for approximating empirical Bayes (EB) estimates in traffic locations (e.g., road segments) which benefits from the modeling advantages of deep neural networks, and its performance is compared in a simulation study with the traditional approach based on negative binomial model (NB-EB). The NB-EB uses negative binomial model in order to model the crash data and is the most common approach in practice. To model the crash data in the proposed CGAN-EB, conditional generative adversarial network is used, which is a powerful deep neural network based method that can model any types of distributions. A number of simulation experiments are designed and conducted to evaluate the CGAN-EB performance in different conditions and compare it with the NB-EB. The results show that CGAN-EB performs as well as NB-EB when conditions favor the NB-EB model (i.e. data conform to the assumptions of the NB model) and outperforms NB-EB in experiments reflecting conditions frequently encountered in practice, specifically low sample means, and when crash frequency does not follow a log-linear relationship with covariates.